Replies

1. 
   JohnWW | Jan 05, 2007 10:43pm | #1

   It probably is mineral oil, but it would be nice to know for sure. 

   If it is a vegetable oil, it may in time polymerize like ordinary finishing oils, in which case you could give the table conventional oil finish that would mix with the oil in the spots and accelerate their hardening.  Mineral oil will never harden so it may affect the adhesion of film type finishes applied over it.

   Any of the common petroleum based solvents, naphtha would be my first choice, will thin out the oil and allow you to blot up much of it with a paper towel pressed onto the solvent soaked spot.  The more times you apply the solvent and then blot up the diluted oil with clean towels the more you will remove.  

   The problem is that you will never be able to remove all of the oil and you will spread the oil that you don't remove wider and probably deeper into the wood.  You will probably be able to tell when you have reached the point where you really aren't picking up much additional oil.

   Once you have removed as much oil as practical, I would go ahead and apply a finishing oil to the table to even out the color between the oil stained areas and the raw unoiled wood.  If a simple oil finish is all you want, you could stop at this point and would probably never have a problem.

   If you want to apply a varnish or lacquer to the table, a thin coat of shellac, or two, will help to seal in the remaining mineral oil and you could probably then apply any finish on top of the shellac with a fair chance that the oil won't affect it.  If you want to be sure of how the remaining oil will affect a film finish you should do a few test pieces and wait a few months to see if the film is stable over the oil before you finish the table.

   Good luck,

   John White